Hoffmann's two-toed sloth

Argyle: Male, wild born in Panama. His birthdate is estimated to be in July, 1974. He arrived at the Zoo on March 30, 1998 from Rosamond Gifford Zoo in New York.

Charlotte: Female, wild born in Panama. Her birthdate is estimated to be in July, 1980. She arrived at the Zoo on March 30, 1998 from Rosamond Gifford Zoo in New York.

Sandy: Female, born at the Philadelphia Zoo on June 10, 2009.

Viewing Hints

Since they are slow moving and mainly nocturnal, you’ll need to look up high in the branches of their exhibit for a clump of fur that is a sleeping sloth.

Where to find me in the Zoo

Small Mammal House and Rare Animal Conservation Center

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Sloths are very unique in form and behavior and are designed for a life spent upside down. Their long guard hairs grow backwards from the belly to the back and have a special grooved structure that encourages algae growth. The algae gives the sloth a greenish tint, which helps them camouflage in the treetops. Their limbs are long and end in toes that are bound together with skin like mittens, with each toe sporting a long hooked claw that allows the sloth to hang from branches with very little effort. Their short tail is only a couple of inches long and their head is short and round with forward facing eyes. When sitting still, they look like a clump of vegetation in the treetops.

Longevity

Sloths typically live 10-12 years in the wild, but can reach into their mid-thirties in captivity.

Behavior

Sloths are well named, as they are one of the slowest moving mammals on earth. They spend nearly their whole life hanging upside down in the trees – even eating, sleeping, mating and giving birth in this position. Because they move slowly when they move at all, their metabolic rate is much less than that of other mammals. Their muscle mass is only 25% of their body weight, half that of other mammals, since they don’t need their muscles to walk or run. They do descend from the trees once a week to defecate and urinate at the base of the tree. This is a very odd behavior and no one is really sure why they do this instead of simply defecating as they hang from a tree. They can’t jump, so if they need to move across treeless areas they must come down to the ground. Unable to stand upright on their legs to walk, they have to crawl across the ground – pulling themselves forward by using their front claws. They are surprisingly good swimmers and take advantage of the rainy season when the forest floor may be flooded to move to new areas by water. Unlike most mammals their body temperature varies considerably depending on their surroundings. This limits them to life in a climate of fairly constant temperature. They have the lowest and most variable body temperature of any mammal. While nearly all mammals have seven neck vertebrae – including both humans and giraffes – sloths have a varying number that ranges from 6 to 8. Needless to say, these are very unique creatures!

Reproduction

There does not appear to be a specific mating season, and a single baby is born after a 11.5 month gestation. The newborn sloth weighs about a pound and immediately grips on to its mother’s fur with its tiny claws. It is able to hang upside down on its own at 20-25 days and regularly feeds away from her at 5 months. They are not fully weaned until 9 months and often remain with their mother for up to two years.

Size

Head and body length ranges from 20 – 30"

Weight

Weight is between 9 – 18 lbs

Diet

The Hoffmann’s two-toed sloth is an herbivore consuming mainly leaves and twigs and occasionally fruit in the wild. These animals are foregut fermenters having a multi-chambered stomach filled with micro flora, which help them digest their food. At the Zoo, sloths are offered a base diet of commercial herbivore food that provides the majority of nutrients the animal requires. The enrichment portion of the diet includes a variety of vegetables, fruit, leafy greens and in the summer leaves and twigs harvested from local trees.

Geographic Range

Two-toed sloths are found in tropical rainforests and cloud forests in Central and South America – ranging from Nicaragua to southern Brazil.

To learn more about the conservation efforts at the Philadelphia Zoo, click here.